Speed responsive apparatus



SPEED RESPONS IVE APPARATUS Filed Nov. 24. 1951 s Sheefs-Sheet 1 BrakeControlling Mayne! Canmnt L Time my. 2. (fitment 1 INVENTORS Tum-9 P9PUtne and 9 Ralph 1000 9.

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THEM/1110mm.

Patented June 6, 1933 UNITED STATES PATENT oFFIcE PER UTNE AND RALPH K.CROOKS, OF EDGEWOOD, PENNSYLVANIA, ASSIGNORS TO THE UNION SWITCH &SIGNAL COMPANY, OF SWISSVALE, PENNSYLVANIA, A COR- PORATION OFPENNSYLVANIA SPEED RESPONSIVE APPARATUS Application filed November 24,1931.

Our invention relates to speed responsive apparatus, and particularly toimprovements in speed responsive apparatus of the type described andclaimed in an application for Letters Patent of the United States,Serial N 0. 551,967, filed by Frank H. Nicholson, on July 20, 1931.

Speed responsive apparatus embodying our invention is particularlysuitable for, although in. no way limited to, use for controllingcircuits in conjunction with speed control systems for railroads.

We will describe three forms of apparatus embodying our invention, andwill then point out the novel features thereof in claims.

In the accompanying drawings, Fig. 1 is a view, partly in section,partly in side elevation, and partly diagran'imatic, illustrating oneform of apparatus embodying our invention. Figs. 2, 3, 4 and 5 arediagrams, showing graphically, the operating characteristics of aportion of the apparatus illustrated.

in Fig. 1. Fig. 6 is a view, similar to Fig. 1, showing a modified formof the apparatus illustrated in Fig. 1, and also embodying ourinvention. Fig. 7 is a diagram, showing graphically, the operatingcharacteristics of a portion of the apparatus illustrated in Fig. 6.Fig. 8 is a View, partly in side elevation, partly in section, andpartly diagrammatic, illustrating another form of apparatus embodyingour invention. Fig. 9 1s a sectional view-taken on the line IXIX of Fig.8. Fig. 10 is a view showing a modified form of a portion of theapparatus illustrated in Figs. 8, and 9, and also embodying ourinvention, and Fig. 11 is a sectional view taken on the line XIXI ofFig. 10.

Similar reference characters refer to similar parts in each of theseveral views.

Referring first to Fig. 1, speed responsive apparatus embodying ourinvention embraces suitable speed responsive circuit interrupting means,designated as a whole by the reference character M, and here shown ascomprising a rocker 1 and an inertia member 2 which cooperates with therocker 1. The rocker 1 is mounted to oscillate about a suitable shaftindicated at 3 in the drawings, and is intended to be operativelyconnected with Serial No. 577,057.

any body or device whose linear or angular speed it is desired tomeasure, in such manner that the frequency of oscillation of the rockerwill be proportional at all times to the speed of the body or device, Inthe embodiment illustrated, the rocker 1 is operatively connected withthe axle 6 and wheel 7 of a car. or locomotive, not shown in thedrawing, by means of a connecting rod 4. The connecting rod 4 is pivotedat one end on a pin 1 carried by an extension 1 on the rocker 1, andatthe other end on a crank pin 5 which is eccentric to the axle 6 andwheel '7. It will be apparent, therefore, that when the wheel 7 isrotated,the rocker 1 will be oscillated at a frequency which is directlyproportional to the speed of the Wheel, the

frequency of the rocker being increased as the.

speed of the wheel increases, and decreased as the speed of thewheeldecreases. It follows, therefore, that the frequency of oscillationofthe rocker will increase ordecrease as the linear speed of thelocomotive or car of which the wheel 7 forms a part increases ordecreases. It should be distinctly understood, however, that theparticular arrangement shown is utilized merely for the convenience indescribing our invention, and not by way of limitation.

, he inertia member 1 is pivotally mounted on a shaft 9 carried by therocker 1 and, in the form'here shown, comprises two spaced weights 2 and2 conn-ectedby integral webs 2 and 2 with a sleeve portion 2 which re-'ceives the shaft 9. Interposed between an arm 11 secured to the weight2- and an adjustable spring support 12 screwed through the web 1 of therocker 1, is a coil spring 13 which biases the inertia member 9 to aposition in'which a contact member 14 secured to the weight 2 engages acontact member 15 attached to, but insulated from, theweb 1 of therocker 1. The spring support 12 is locked in an adjusted position bymeans of a lock nut 16.

The apparatus also includes a reactance X and an electroresponsiveindicating device, here shown as a relay R. The reactance X and relay Rare connected in series in a circuit which passes from terminal B, of asuitable source of current not shown in the drawing, through rocker 2,contact 1% 15, reactance X, and the winding of relay R to the otherterminal O of the source. Connected in multiple with reactance X andrelay R in the circuit just raced is an asymmetric unit A which is sodisposed that it will offer its highcst res stai ce t) current whichtends to flow through the branch path including this unit from terminal.B to terminal of the source. Relay R is nferably made slowacting for re:sons which will a ipear as the description proceeds.

"rho operation, as a whole, of the apparatus thus tar des bed is asfollows: As previousiy poinced out, vhen the wneel 7 is rotated, therocker 1 is oscillatec ata frequency which incrc; cs as the speed ofrotation of the wheel T increases. At all frequencies of oscillation ofthe rocker, the motion ot the rocker is substantially simple harmonicmotion, and itwill be apparent, lherci'or that when the rocker isoscillatin it causes an accelerating to co to be exerted which variesaccording to a sine curve. 'inzs accelerating force is alwavs inopposition to the tcrce causing the displa ement of the rocker from theposition in which it is shown in Fi and it will be readily understoodthat during that portion of each oscillation in which the lOCliLl isbeing rotated in a clockwise direction from the position shown in Fig".1, this accelerating force is transmitted to the rocker through thespring 13. That is to say, during that portion 0t each oscillation inwhich the rocker 1 is being rotated from the position shown in Fig. l ina clockwise direction, the accelerating force of the inertia member isopposed by ,the force of the spring 13. The magnitude of theaccelerating force acting on the inertia member increases with increasesin the fre quency of oscillation of the rocker according to the squareof the trequency, and it will be seen, therefore, that as long as thefrequency of oscillation of the rocker remains below some frequencywhich we shall term the critical tr-eruicucy. and which depends upon theproportioning of the parts, the accelerating force acting on the inertiamember will always be less than the opposing force of spring and underthese conditions, contact ii-l5 will remain continuously closed. issoon, however, as the frequency of oscillation of the rocker increasesbeyond this critical. frequency, a condition will be reached during someportion of each osrilla'ltion in waichthe accelerating force acting onthe inertia member is greater than the opposing force on the spring, andwhen this happens, the spring will no longer be able to hold the inertiamember against the rocker, with the result that the spring will becomecompressed and permit contact to open. hen the contact has once opened,the motion of the inertia member is governed by the inertia of theinertia member and by the opposing force of the spring. The opposingforce of the spring depends, among other things, upon the relative positon ot the inertia member with respect to the rocker, and it will beclear, therefore, that alter the contact has once opened, the inertiai'neinber will continue to move in the direction to increase the contactopening for a time, but will soon come to rest, and will then move withincre sing velocity in a direction to again close the contact.Considering the motion of the rocker during this time, it is evidentthat its acceleration in- ?rea es to a negative maximum as it comes torest at the end of its stroke in the clockwise direction of rotation,and then decreases as it moves in the opposite direction, becoming zeroat mid stroke. At some point after the rocker has reversed the directionof its rotation from clockwise to counter-clockwise. the acceleration oithe rocker vill be less than that which caused the contact to open.\Vhen this happens, the rocker and inertia member will each be moving inthe colintor-clockwise direction. and the inertia member will bezmcclerating at a rapidly increasing rate. It is evident, therefore,that the contact will again become closed during each oscillation atsome later point in the cycle than the point at which it opened. Sincethe acceleration of the inertia member varies as the square of thefrequency of oscillation of the rocker. it follows that the length ofthe open time of contact l-ll;l5 during each oscillation will rapidlyincrease, and the length of the closed time will rapidly decrease, withslight increases in the frequency of oscillation of the rocker beyondthe critical frequency. It should be pointed out, that, since for agiven proporlioning of the parts, the weightof the inertia member andthe relative locations oi the shafts l) and 23 are fixed, the criticalfrequency at which contact il -15 lirstopens, may be varied by varyingthe adjustment of the spring 13.

As was previously pointed out, contact ll lo is included in the circuitfor reactance X and relay R, and it follows that when contact l-'l-15 isclosed, this circuit will be closed, and current will therefore besupplied to the winding of relay R. It will be readilv understood,however, that due to the inductance of this circuit the current in thewind-- ing of the relay will not build up to its Ohms law valueimmediately upon the closing of this contact, but will follow a timeconstant curve similar to the curve 18 shown in Fig 3. Likewise whencontact 1+ll5 is opened, the circuit for reactance X and relay R willbecome interrupted, and the supply of current to the relay willtherefore be cut oil. At the instant the supply of current to the relayis cut oil, the current in the winding of the relay will start todecrease, but due to the of contact ll15 increases, and the closed timedecreases, as the frequency of oscilla' to a lower value. Theperiodically varying energy stored in this winding and in reactance X, acirculating current will be set up in the closed circuit including thewinding of the relay, reactance X, and asymmetric unit A, and thiscirculating current will delay the decay of current in the winding ofthe relay in a manner which is indicated graphically by the timeconstant curve 17 shown in Fig. 2. It will be seen, therefore, that ifcontact 1 e 15 is alternately opened and closed at a fixed rate, as isnormally the case when the rocker is being oscillated at any constantfrequency above the critical frequency, the current in the winding ofthe relay will first decrease during each oscillation along some portionof the curve 17 to some value which depends upon the initial alue of thecurrent in the winding of the relay at the instant contact l t-15 becameopened, and upon the length of time the contact remains opened, and willthen increase along some portion of the curve 18 to the same value whichit had when the contact last became opened. This grmvth and decay of thecurrent in the winding of relay R at one particular frequent-y ofoscillation of the rocker above the critical frequency indicatedgraphically by the curve 20 shown in Fig. l. Referring to this ligure,the line ?)-0 of the curve 20 represents the decrease in current in therelay Winding during one oscillation, and the line c-Z) indicates theincrease in current during the same oscillation. During the nextsucceeding oscillation, the decrease in current is represented by theline b c and the increase in current by the line 0 -45 etc. It will beseen, therefore, that at one particular frequency of oscillation of therocker above the critical frequency, the winding of the relay will besupplied with a periodically varying current, the average value of whichis indicated by the line 21 in Fig. 4.

As described hereinbefore, the open time tion of the rocker increasesbeyond the critical freq uency. It will be readily understood,therefore, that at the higher frequencies of oscillation of the rocker,the current has less time to build up, and consequently does not buildup to such a high value as it d oes at the lower frequencies. Also,since the open time of the contact is greater, the current decayscurrent which is supplied to the relay winding when the rocker isoscillating at a frequency which is somewhat higher than the frequencyof oscillation corresponding to that for the curve 20, is indicated bythe curve 22 shown in Fig. 4, and the average value of the current whichis supplied to the relay winding under these conditions is indicatcd bythe curve 23. From a comparison 0f the curves 20 and 22, it will be seenthat as the frequency of oscillation of the rocker increases beyond thecritical frequency, the average current in the relay winding decreases.

Referring now to Fig. 5, the curve 24: here shown a typical curveindicating the man her in which the average value of the current whichis supplied to the relay winding varies with variations in the frequencyof oscillation of the rocker 1 for one particular proportioning of theparts. From an inspection of this curve it will be seen that, at allfrequencies below the critical frequency, the average value of thecurrent in the relay winding is substantially constant. The reason forthis is that, since contact l415 remains closed at all frequencies belowthe critical frequency, the current in the winding of the relay buildsup to, and remains at, its Ohms law value. As soon as the frequency ofoscillation of the rocker passes the critical frequency, however, sothat contact 1 l15 starts to periodically open and close, the averagevalue of the current in the relay winding starts to decrease, and as thefrequency of oscillation of the rocker continues to increase, thecurrent decreases more and awe rapidly until, at a narrow band offrequencies ust a little above the critical frequency, the decrease isvery rapid. As the frequency further increases beyond this narrow bandof frequencies, the decrease in current becomes less marked until afrequency is finally reached at which the rate at which the contact14-15 interrupts the circuit for the reactance X and relay R becomes sohigh that substantially no further decrease in current takes place.

As was pointed out hereinbefore, relay R is a slow-acting relay, and itwill be readily understood, therefore, that by properly proportioningits parts, this relay may be made to respond to the average value of thecurrent supplied to its winding, and not to the instantaneous value. Itwill be seen, therefore, that by constructing this relay to have picleupand release values which fall on some portion of the curve 24, the relaywill be picked up at all fIOQHOUCiQS of oscillation of the rocker bclowthe frequency corresponding to the picle up value, and will be releasedat all frequencies of oscillation of the rocker above the fre quencycorresponding to the release value.

For example, if the relay. is provided with the lay will remain 1L atwhicl v.re relay picks up is passed. Itw1ll he rcincniocrcd that thecritical frequency of the roclter depends upon the proportioning of theparts, and that for a given proportioning of the pa: is. this frequencymay be varied by adjusting the position of the spring support 12 to varythe biasing force exerted by the spring 12'}. ll ill be seen, therefore,that by p 'operly selecting the electrical and mechanical elements ofthe apparatus, and by properadjustin' the biasing force of the springrelay may be made to pick up and release its armature at any desiredfrequency of oscillation of the rocker. and hence, at any desired linearspeed of the car or locomotive with which rocker is o ieratively connectcd. It will also be seen that by adjusting the pick-up and releasevalues of the relay R to such values that they fall on the steep portionof the curve as indicated by the lines 25 and :26, the relay may be madeto pick up and release its armature at frequencies which (lifter inmagnitude by only a small amount. "lhis particularly desirable when therelay is to be utilized for controlling circuits in connection withspeed control systems for railroads.

When relay R is picked up, its front contact 1919- is of course closed,and when the relay is 'eleascd, its back contact 1919" is closed. Thecontacts of the relay may be utilized to control the circuits for anysuitable clcctro-responsivc device or devices in such manner that thedevice or devices will occupy one condition when the relay is energizedand another condition when the relay is deenergized. For example, whenthe apparatus is operativcly connected with some part oi. the runninggear of a car or locomotive, as is the case in the embodimentillustrated, so that the frequency of oscillation of the rocker 1 varieswith the linear speed of the car or locomotive, relay ll may be utilizedto control a speed governing device for the car or locomotive. As hereshown, relay R controls a brake controlling magnet E which applies thebralzcs on the car or locomotive when this magnet bet-or deencrgized.The circuit for magnet E is carried over front contact ilk-l9 of re ayR. t will be apparent, therefore. from the foregoing, that as long asthe speed of the car or locomotive is below some predetermined speed,magnet E will be energized. but that if the speed of the car orlocomotive increases beyond this speed, magnet E will becomedeencrgized, thus enforcing a low speed limit on the car or locomotive.It should be definitely understood, however, that apparatus embodyingour invention is in no way limited to this particular use.

Referring now to Fig. (3, the apniratus here shown is similar to thatshown in Fig. l with the exception that the inertia member of thecircuit interrupting means, which circuit interrupting means is heredesignated generally by the reference character M instead of beingbiased by means of the spring 13 to the position in which the contz ctl4- is closed as shown in Fig. 1, is biased by means of a spring 58 tothe position in which the contact li-15 open. The spring 58 is securedat one end to the arm 11, and at the other end to an adjustable eyebolt5t) which is screwed through the web .l" of the rocker 1. The eyebolt 59is loclicd in place by means of a nut (30. An adjustable stop (ll limitsthe amount of opening of the contact i l-15.

With the apparatus constructed as shown in Fig. when the rocker l isoscillated. the inertia of the inertia member will aid the spring 58 inholding contact ll-i5 open (llll'llh-j a portion of each oscillation butwill tend to s-ttretch the spring. and hence to close the contactl-l--l5, (ltll'lllgl' another portion of each oscillation as will beread ly undo"- stood from the foregoing description of Fig. 1. It willbe apparent. therefore, that as long as the frequency of oscillation ofthe rocker remains below some critical frequency which depends; upon theproportioning of the parts and the :nliu:-:t1nent of the spring 58,contact l ll5 will constantly remain open, but that. as soon as thefrequency of oscillation of the rocker becomes greater than thiscritical frequency, contact lslil5 will start to alternately open andclose, the length of the closed time increasiinr, and the length of theopen time decreasing. as the frequency of oscillation of the rockerincreases beyond the critical frequency. As previously pointed out inconnection with Fig. 1. when contact i l- 15 is open, the circuitforreactance X and relay It is inter ruptcd, and the current in the windingof the relay decays. lVhcn this contact is closed, however. the circuitfor reactance X and relay R is then closed, and the current in the relaywinding builds up. .lt follows. therefore, that as long as the frequencyof oscillation of the rocker is below the critical frequency, relay Rwill constantly remain decnergized. As soon. however, as the fre quencyof oscillation of the rocker becomes greater than the critical frequencyso that contact 1a15 becomes al ernatcly opened and closed. the windingof the relay will be supplied with a periodically varying current, theaverage value of which will increase as the frequency of oscillation ofthe rocker increase. The manner in which this increase takes place forone proportioning of the parts is indicated by the curve 62, shown inFig. 7. Referring to this figure, it will be observed that as soon asthe critical frequency of the rocker ispassed, the average value of thecurrent supplied to the relay winding first increases gradually and thenmore and more rapidly until a narrow band of frequencies is reachedbetween which the increase is very rapid. As the frequency increasesbeyond this narrow band of frequencies, the increase in current becomesless rapid until a frequency is finally reached where very littlefurther increase in current takes place, and the average value of thecurrent for further increases in the frequency of oscillation of therocker then remains substantially constant. Since relay R is constructedto respond to the average value of the current supplied to its winding,it fol lows that by providing the relay with pickup and release valueswhich fall on the curve 62, the relay will be released at allfrequencies of oscillations of the rocker below the frequencycorresponding to its release value, and will be picked up at allfrequencies above that corresponding to its piclcup value.

When the parts are arranged as shown in Fig. 6, relay B may be utilizedto control any suitable device in any desired manner. Referring now toFigs. 8 and 9, in the moditied form of our invention here shown, thecircuit in terrupting: means is designated as a whole by the referencecharacter M and is enclosed in a suitable casing C, which may, forexample, be secured to some stationary part 31v of the car or locomotivein such manner that iis position with respect to the axle 6 of the carwill remain fixed. ()ne side wall 33 of the casing; C is formed with abearing 30, and the opposite side wall 34 thereof is provided with anopening 35. The opening 35 is closed by a suitable cover plate 36 havinga bearing 29 formed therein which is in axial alignment with thebearing' 30. A horizontally extending shaft 38, to which a rocker 1rigidly secured, is iournalled in the bearings 29 and 30. and theright-hand end 38 thereof extends through the casing and is providedwith a era 1; 37. The free end of the (I'Ellsll' 37 is pivotally(7011110. l with the upper end of the connecting rod lpreviouslydescribed in connection with Fig. 1. It will be seen, therefore, thatwhen wheel 7 is rotated, the rocker 1 will be oscillated at a frequencywhich increases as the speed of the wheel. and hence as the linear speedof the car, increases. For reasons which will appear hereinafter, therightdiand end 38 of the rocker 1 is made tubular, and extendingfrom theinterior of the casing through this tubular portion into the openingtherein are a plurality of holes 39,.as clearly shown in Fig. 8.

Pivotally mounted on the shaft 38 between bosses 38 and 40 formed on therocker 1 are a plurality of inertia'inembers 2, 2, and 2 Each of theseinertia members is similar to the inertia member 2 shown in Fig. 1, andeach is biased. by means of an associated adjustably spring 13 125 or tothe position in which a contact finger 14, 14?, or 14 carried therebyengages a fixed contact member 15, 15 or 15 carried by the rocker, aswill readily be understood from an inspection of Figs. 8 and 9. Externalelectrical connections to all of the contact fingers 14 is made by meansof a flexible conductor 41 which ex tends through the opez' ing in thetubular portion 38* of the r her 1 and through one of the holes 39, andwhich is fastened'to each inertia member by means of a suitable screw45. External. electrical connections to the fixed contact members 15. 15and 15 are similarly made by means of flexible conductorsll, 43 and l4,respectively, each of which extends through a different hole 39 into theopening 38 in the tubular end of the rocker 1 and is soldered orotherwise fastened at its inner end to the associated fixed contactme1n'' her. i

The contact 14E 15 controls the supply of current to an electricalcircuit which passes from terminal 13 of the source through flexibleconductor 41, inertia member 2 contact 1.4 15 flexible conductor 42, andan asymmetric unit A connected in multiple with a reactance X and thewinding of a relay B9 in series, to terminal 0 of the source. Thercactance X, relay 11 and asyminetricu'nit 'A are similar in allrespects to the reactance X, relay B and asyimnetric unit A. previouslydescribed in connection with Fig. 1. The contacts Li -15 and le -15control the supply of current to similar circuits which will be a'aparcnt from the drawings without describing them in detail.

The o 'ieration of the apparatus shown in Figs. 8 and 9, in so far asthe elements associated with each inertia member is concerned,

is substantially the same as that previously described'in connectionwith Fig. 1, and will be readily understood without further description.It should be pointed out, however, that by properly adjusting thesprings 13 associated with the different inertia menibers, the contacts14 -15, la --15 and 1 l 15 may be made to first open at differentfrequencies of oscillationof the rocker 1, and under these conditions,the relays R", R and ll will operate at different speeds of the car orlocomotive. thus enabling a plurality of different speed limits to beenforced on the car or locomotive.

Referring now to Figs. 10 and 11, we have here shown a modified form ofthe circuit interrupting apparatus illustrated in Figs. 8 and 9. As hereshown, the rocker 1" cooperates with tl ee inertia members 2, 2

and 2, each of which is in the form of a. substantially rectangularblock. Each of the inertia members is pivotally mounted on the shaft 38.and has secured to its face which is nearest the web of the rocker i aleaf spring 46, $6 or 46. The upper ends 01" the leaf springs l6, 16 and46* are provided with Contact tips 4T. 47* and 47*. respectively, whichcooperate with similar contact tips l8, only the. tip l8 whichcooperates with the contact tip 47* being visible in the drawings. Thecontact tips 48 are each fastened to the upper ends of a fixed contactmember 49, and the contact members 49, in turn, are fastened to, butinsulated from the rocker l. The lower ends of the leaf springs 46*, T6and 46 cooperate with suitable adjusting members 50, 50 and 50 in suchmanner that the inertia members are constantly biased by the springs tothe positions in which the contacts etT 48, 47 '48 and *l7 4.-8 areclosed. It will be apparent, therefore, that the leaf springs to serveboth as contact fingers and as biasing means. The adjusting members 50,5O and 5d are screwed through threaded holes in the web of the rocker l,and in the form here shown. each adjusting member comprises av metalplug 50 provided at its inner end with an insulating insert 56 whichinsulates the adjacent leaf spring from the rocker. Each adjustingmember is maintained in its adjusted position by means of a lock washer52 having a threaded hole 53 which receives the nieinber (see Fig. 11)and an integral lug tl'irough which a screw 54 which is screwed into thelOt'liQi 1 passes. To lock an adjusting member in an adjusted positionithe associated washer 512 is screwed onto the adjusting member to aposition in which it is spaced a slight distance from the rocker. andthe screw 5st is then tightened, thus binding the threads of theadjusting member. and hence preventing it from turning. It will be notedfrom an inspection of Fig. 10 that the lower portion of the inertiamember 2 adjacent the spring lt) is curved as indicated at 57 in thedrawings. This curvature is so shaped and arranged that the free end ofthe spring 46 becomes shorter and rapidly increases in stiffness as soonas the contact l i-15 has opened. This feature is important particularlywhen a comparatively heavy inertia member must be adjusted to open thecontacts at a comparat-ive ly low speed and at the same time be capableof properly following the oscillations of the rocker at higher rates ofspeed without an excess opening of the contacts. The curvature of thelower portion of the inertia member also tends to decrease wear betweenthe parts. The other inertia members are likewise cnrved in a similarmanner. In the structure shown, it is intended that the contacts -LtT48, 47 -etS and 47 48 shall first open at difierent frequencies ofoscillation ot the rockers, and in order to facilitate this operation,the mass oi the inertia member which operates the contact which isintended to First open at the highest 't'rc picncics of oscillation ofthe marker is made somewhat less than the mass of the inertia memberwhich operates the contact which is intended to open at the next lowerfreipicncy of oscillation of the rocker. etc. as wi l be clearly a iparent from an inspection of Fig. 10.

lVith the circuit interrupting means constrncted as shown in Fig. it)when the rocker 1 is operated, 'l-fjll inertia member cooperates wiihthe rocker to control z'b associated contact in substantiz li the samemanner as the rocker 2 shown in Fig. 1 cooperates with the rocker 1 tocontrol the contact 1=l-15. The parts are so proportioned, however, andthe springs 50 are so adjusted that the coin tact -l7 -4r.8 will firstbecome periodically opened and closed at a relatively low frequency ofoscillation of the rocker, the contact ai -4 :3 at a somewhat higherfrequency of oscillation of the rocker. and the contact std-l8 at astill higher frequency.

The circuit interrupting means shown in Figs. 10 and ii is intended tobe utilized in the same. manner as the circuit interrupting means Mshown in Figs. 8 and Y). and when utilized in this manner. the operationof the apparatus as a whole. will be readily understood from theforegoing without describing it in detail.

Although we have hcrein shown and described only Your form of :1p""'itus' eml'uuiying our invention. it is unde tood that wax-ionschangesand modifi ations may be maoc therein within the scope ot the appendedclaims without departing from the spirit and scope of our invention.

Having thus describcijl our invention, what we claim is:

1. Apparatus for indicating the speed of a movable body comprising afirst men'iber adapted to be oscillated at a frequency which varies withthe speed of the body, an inertia member pivotally mounted on said firstmember, a fixed contact member carried by said first member. a. secondcontact member carried by said inertia member. a spring carried by saidfirst member and arranged'to bias said inertia member to a position inwhich said second contact member engages said lined contact member, andan electrorcsponsive indicatii'ig device controlled by the contacttorn'ied by said second contact member and said lixcd contact member.

2. Apparatus for indicating the speed of a movable body comprising afirst member adapted to be oscillated at a trcquency which varies withthe speed of the body. an inertia member pivotally mounted on said firstmember. a fixed contact member carried by said first member, a secondcontact member carried by said inertia member and adapted to cooperatewith said fixed contact member, a spring secured to said first memberand to said inertia memb and arranged to bias said inertia member to theposition in which the contact formed by said fixed contact member andsaid second contact member is open, and an electrcresponsive indicatingdevice controlled by the contact formed by said fixed contact member andsaid second contact member.

3. Apparatus for indicating the speed of a movable body comprising afirst member adapted to be oscillated at a frequency which varies withthe speed of the body, an inertia member mounted to oscillate about thesame axis as said first member, a fixed contact member carried by saidfirst member, a second contact member carried by said inertia member, aspring carried by said first member and arranged to bias said inertiamember to a position in which said second contact member engages saidfixed contact member, and an electroresponsive indicating devicecontrolled by the contact formed by said second contact member and saidfixed contact member.

4. Apparatus for indicating the speed of a movable body comprising afirst member adapted to be oscillated at a frequency which varies withthe speed of the body, a pivoted inertia member, a fixed contact membercarried by said first member, a second contact iii-ember carried by saidinertia member, a spring carried by said first member and arranged tobias said inertia member to a position in which said second contactmember ongages said fixed contact member, and an electrical circuitcontrolled by the contact formed by said second contact member and saidfixed contact member, said circuit including an asymmetric unitconnected in multiple with a slow-a itii'ig relay anda rucactance inseries.

5. Apparatus tor indicating the speed oi a movable body comprising afirst member which is adapted to be oscillatedat a fr quency whichvaries with the speed. of the body, a p urr inertia members pivotal-..ity oi 1v mounted on said first member, a plurality oifixed contactmembers carried bv said first member, plz'raiity or other contactmembers one attached to each inertia member and each adai'ited tocooperate with a different one of said fixed contact members, a.plurality oi springs carried by said first member and each arranged tobias :1 different one of said inertia members to the position in whichthe contact incmliier -rarried by the associated inerti engages theassoci; ted fixed being adjusted to exert ditl'crcnt biasing forces, anda plurality of clcctrm-osponsivc indim 'ing devices one controlled bythe contact formed by each said other contact member and. the associatedfixed contact member.

6. Apparatus for indicating the speed of a movable body comprising afirst member which is adapted to be oscillated at a frequency whichvaries with the speed of the body, a pin 'ality of inertia membersmounted to oscillate about the same axis as said first member, aplurality of fixed contact meniibers carried by said first member, aplurality of other contact members one attached to each inertia memberand each adapted to cooperate with a different one of said fixedcont-act members, a plurality of springs carried by said. first memberand each arranged to bias a different one of said inertia members to theposition in which the contact member carried by the associated inertiamember engages the associated fixed contact, said springs being adjustedto exert different biasing forces, and a plurality of electroresponsivein d' rating devices one controlled by the contact formed by each saidother contact member and the associated fixed contact member.

7. In speed responsive apparatus for electrically indicating the speedof a movable body by periodically interrupting the supply of current toan inductive electrical circuit including an electroresponsiveindicating device which is selectively responsive to the average valueof the current in its winding,

in combination. circuit interrupting means comprising a first memberos-illated at a speed which va ies with the speed or" the body, aninertiamember pivotally mounted on said first member, a fixed contactmen'iber secured to said l.l1Sl31110111l)61', a second contact membercarried by said inertia member, and a spring carried by said firstmember and arranged to bias said inertia member to a position in whichsaid second contact member engages said fixed contact member.

8. In speed responsive apparatus for electrically indicating the speedoi: a movable body by periodically interrupting the supply of current toan inductive electrical circuit including an electroresponsiveindicating device which is selectively responsive to the average valueof the current in its winding, in con'ibination, circuit interruptingmeans comprising a first member oscillated at a speed which varies withthe speed of the body, an inertia member pivotally mounted to oscillateabout the same axis as said first member, a fixed contact member securedto said first member, a second contact member carried by said inertiamember, and a spring carried by said first member and. arranged to biassaid inertia member to a position in which said second contact memberengages said fixed contact member. I

9. In speed responsive apparatus for elec trically lndicati. the spe dof a HIOVtIblQ p whi h a rerage value c l the current in. its wind inn,in combination, ri rcuit iuterr nling means comprising); a first memberoscillated at a speed 'arics with the speed of the body, a plurality ofinertia members pi votally mounted to ()FKlllZitC about the same axis assaid lirwt member, a plurality of fixed contact members carried by saidfirst member, a plurality of other contact members one carried by eachinertia member and each adapted to cooperate with a different one ofsaid fixed contact memb rs, and a plurality of springs by said firstmember and each (1'- to bias a difierent one of said inertia nein ers tothe position in which the contact mcnibe' carried by such inertia memberengage the associated iiried contact member, said springs being adjustedto exert difl'erent biasing forces.

10. In speed responsive apparatus for elecdly iniilicating the speed ofa movable Jody by i ieriodically interriipting the supply oi irrent toan 3 Inductive electrical cir- -;r an eiectroresponaive indicatis slcctivcl -r responsive to 10 current in its Windcombii ation. circuitinterrupting a first member oscillated ii-"n c i] h avcra ye value oitat a spcco \rnirh varies w th the speed of the an inert a memberpirotally mounted to osriilat' about the same axis as said first contactmember carried by he a leat spring; secured ti V iber and provided atone end -"liii a contact tip which cooperates with said lixcd contactmemb r. and 11;}276 carl'ic 'l b) said, first contact member andeoope'ating with the other end oi said leai' spril'ig in such mannersaid spring biases said numbcr to the pwiiion in which sa d contact tipencontact member. Kfli resnonsivc ai'iparatus tor electhe speed oi, amovable ly interrupting the sup- 2 inductive electricalcirlectroresponsive indicats selectively responsive to of the current inits windiom circuit interrin'iting a first member oscillated with thespeed of t 1e iemoer pivotally mounted to oscillate be same axis saidfirst membe d con act member mirried by said lir.-;t member. a leatspring secured to said irerlia nicnihc and pr( vided at one end wit acontact tip which cooperates with said iixr-d cont ct member. and apluit adjustably i'l' U'i i said first mem er and pro- .ts inner endwith an insnlr-iting insert w ich cooperates with the other end ofspring in such manner that, said y es said member to the pos tion inivhich said contact tip engages said fixed contact member.

mendcr. a

l w. Dill ll. in s "h ram an irerti in 12. 1\1) 7Uf21tUH for imlicatingthe speed of a mo able body comprising a lirst member adapted to beoscillatei'l at a 'frcqueiuiy which varies with the speed oi the body, 7pivoted inertia. n'em cr. a fixed contact member rarl'icd by said firstmember. a second Contact member carriml by said inertia member. a springcarried by said first member and arranged to bias said inertia member toa position in which said second contact member engages said fixedcontact member, means for adju ting the biasing; force exerted by saidspring, and an eleetrorcsponsive indicatin; device controlled by thecontact formed by said second contact member and said fixed contactmember.

13. Am aratus for indicating; the speed ot a movable body eomprising; afirst member adapted to be oscillated at a Frequency which varies withthe speed of the body. a pivoted inertia member. a iixed contact membercarried by said first member. a second contact member carried by saidinertia IIIODd'XH. a spring carried by said first member and arranged tobias said iner in. member to a po siti n in which said second contactmember engages said fixed contact member. means for adjusting thebiasing force exerted by said spring. be parts bein c so pro mrtionedthat at. all frequencies of oscillations oi said first member above apredetermined treqnency the inertia of said inertia member will saidspring nce du 'ing each oscillation ently to open the contact lormcd bysaid second contact meinliicr and said fixed c-rintaet member for aninterval of time which increases as the speed of the body increases, andan clectroresponsive indicating: device controlled by the contact formedby said second contact member and said fixed contact member.

H. Ap nirat-us For indicating the speed of a movable body comprising afirst member adapted to be oscillated at a Frequency which varies withthe speed of the body, a pivoted inertia member. a fixed contact membercarried by said first member, a second contactmember carried by saidinertia member a spring carried by said irst member and arranged to biassaid inertia member to a position in which said second contact memberengages said fixed contact member, means l'or adjusting the biasin;force exerted by said spring. the parts being so proportioned that atall frequencies of oscillation of said irst member above a predeterminedl re- (incur-y the inertiav of said inertia. member will stress saidspring: once during each oscilia-jinn suliiciently to open the contactformed by said second contact member and said fixed contact member foran inter al of time \vhic increases as the speed of the body increases,and an electroresponsive indicatin; device controlled by the contact-'t'ormed by said second contact member and said fixed contact member andselectively responsive to the proportion of the open time of saidcontact to a fixed interval of time.

15. In speed responsive apparatus, the combination of a first memberoperated through successive cycles at different frequencies, an inertiamember pivoted on the first member and sustaining from the movement ofthe first member a secondary motion, and means connecting the inertiamember with the first member and constantly urging the two members to adefinite relative position with a force derived partly from themovements of the members and tending to produce a critical conditioncorresponding to a definite frequency of the first member beyond which acyclic change in the relative positions of the two members takes place.

16. In speed responsive apparatus, the combination of a first memberoperated through successive cycles at different frequencies, an inertiamember pivoted on the first member and sustaining from the movement ofthe first member a secondary motion, a first contact member carried bythe first member, a second contact member carried by the inertia"member, and means con necting the inertia member with the first memberand constantly urging the inertia member to the relative position withrespect to the first member in which said second contact member engagessaid first contact member with a force derived partly from the movementsof the members and tending to produce a critical condition correspondingto a definite frequency of the first member beyond which a cyclicseparation of the two contact members takes place.

17. In speed responsive apparatus, the combination of a first memberoperated through successive cycles at different frequencies, an inertiamember pivoted on the first member and sustaining from the movement ofthe first member a secondary motion, a first contact member carried bythe first member, a second contact member carried by the inertia member,and means connecting the inertia member with the first member andconstantly urging the inertia member to the relative position witlfrespect to the first member in which said second contact member engagessaid first contact member with a force derived partly from the movementsof the members and tending to produce a critical condition correspondingto a definite frequency of the first member beyond which a cyclicseparation of the two contact members take place, the duration of whichseparation varies rapidly with slight changes in frequency beyond thecritical frequency.

In testimony whereof we afiix our signatures.

PER UTNE. RALPH K. CROOKS.

